CNC Machine Controller Research Articles

Calculating G-code for CNC machine using the Mamdani fuzzy logic inference system

The widespread desire to automate the CNC machine control process and optimize it is leading to the development of new algorithms. The article presents both a novel approach to this task based on a fuzzy decision-making system as well as an evaluation of the proposed solution on a large database containing data from multiple machining processes and a comparison with the Reference Points Realization Optimization (RPRO) algorithm used in industry. In addition to achieving the intended accuracy of the machining process, the presented system is also easily interpretable for the expert operating the machine. It is also possible to manipulate the presented system easily and shape it according to specific needs.

CNC Machine Control Using DeepReinforcement Learning

Optimization of industrial processes such as manufacturing or processing of specific materials is a point of interest for many researchers, and its application can lead not only to speeding up the processes in question, but also to reducing the energy cost incurred during them. This article presents a novel approach to optimizing the spindle motion of a computer numeric control (CNC) machine. The proposed solution is to use deep learning with reinforcement to map the performance of the Reference Points Realization Optimization (RPRO) algorithm used in industry. A detailed study was conducted to see how well the proposed method performs the targeted task. In addition, the influence of a number of different factors and hyperparameters of the learning process on the performance of the trained agent was investigated. The proposed solution achieved very good results, not only satisfactorily replicating the performance of the benchmark algorithm, but also, speeding up the machining process and providing significantly higher accuracy.

Multibody dynamic modeling of five-axis machine tool vibrations and controller

A computationally efficient, reduced-order multibody dynamic model of a five-axis machine tool is presented. The machine tool is modeled by substructures assembled via flexible springs and damping elements at interfaces which affect the machining performance. NC tool path commands are processed by the linear acceleration-based motion trajectory filters and fed to the axis servo controllers through an inverse kinematic model of the machine. The computed motor torque commands are applied to the structural dynamic model of the machine at the motor connections. The experimentally validated model predicts the performance of the five-axis CNC machine's controller along the tool path.

Synthesis of the CNC machine control algorithms optimized with respect to the contour error using the genetic algorithm

Traditionally control systems of CNC machines are built using the positional system structure, e.g. the uncoupled system (US) tuned on the symmetrical optimum. These systems have a relatively small contouring quality factor–the ratio of the contour speed to the contour error. To increase the quality factor of such systems, we proposed two new algorithms: the US tuned on the contour error optimum (US-C) and the neural coordinated control algorithm (NCCA). Both algorithms were tuned on a non-convex criterion using the genetic algorithm which allowed us to reduce the tuning time and acquire better optimal values of the criterion in comparison to the gradient descent method. The experiments were conducted using a mathematical model of a CNC machine based on real servo motors and lead screws. The results of the experiments showed that the usage of the proposed algorithms led to a significant increase in the quality factor, which has a positive effect on the overall productivity of the CNC machine. Furthermore, the NCCA use available resources better than the other tested algorithms which can be seen in the experiments with a lower initial contour error, a lower radius of the circle, and a higher contour speed. Besides, the US-C can maintain the contour speed better than other tested algorithms.

AN OVERVIEW OF DIRECT OR DISTRIBUTED NUMERICAL CONTROL IN COMPUTER NUMERICAL CONTROL APPLICATIONS

Direct numerical control is also known as distributed numerical control (also abbreviated DNC), is a common manufacturing term for networking CNC machine tools. On some CNC machine controllers, the available memory is too small to contain the machining program (for example machining complex surfaces), so in this case the program is stored in a separate computer and sent directly to the machine, one block at a time. If the computer is connected to a number of machines it can distribute programs to different machines as required. Usually, the manufacturer of the control provides suitable DNC software. However, if this provision is not possible, some software companies provide DNC applications that fulfill the purpose. DNC networking or DNC communication is always required when Computer-Aided Manufacturing (CAM) programs are to run on some CNC machine control. Wireless DNC is also used in place of hard-wired versions. Controls of this type are very widely used in industries with significant sheet metal fabrication, such as the automotive, appliance, and aerospace industries. A DNC system has to fulfill two basic tasks such as first guaranteeing secure, timely data transfer from and to the CNC controllers, secondly administering many thousands of NC programs.

THE TECHNOLOGY OF CHOOSING CNC MACHINE CONTROL METHOD UNDER UNCERTAINTY

Problem. A big market saturation makes very hard finding for optimal solution for manufacture, besides you’ve to take look not only at CNC machines and its parameters but also at CNC machine control methods. By CNC machine control methods means methods for creating controlling programs. The main methods are manual programming, programming by CNC stand, programming with CAD/CAM systems. Goal. The goal of the paper is to ease choosing the CNC machine control method by developing the technology of choosing the CNC machine control method under uncertainty. Methodology. The article has categorized the types of CNC machines and their control methods. Based on system analysis of currently existed works, was created an algorithm, fuzzy math model which consists of fuzzy input and fuzzy output, and the technology of choosing the CNC machine control method itself. Results. Generalized and partial problems of choosing the CNC machine control methods are formulated; the fuzzy math logic model is developed; an algorithm based on the developed fuzzy math logic model is created and further implemented in the technology of choosing the CNC machine control method under uncertainty. Originality. The fuzzy logic math methods have developed in a new subject. Were defined linguistic variables for the CNC parameters, generalized fuzzy input, and output for choosing the CNC control method under uncertainty. Previously generalized fuzzy input and output has been transformed into an algorithm. Practical value. A created algorithm that was based on fuzzy math logical model was added to the technology of choosing the CNC machine control method under uncertainty.

Waste Heat Recovery from CNC Machine Control Panel

Waste Heat Recovery from CNC Machine Control Panel

The Role of Postprocessor in the Translation of Vector Graphics Understandable to the CNC Machine Controller

The purpose of this paper is to show the post-processor role and importance in the creation of programming code which CNC machine controller can understand and proceed. Today, the use of CNC technology introduces the Industry 4.0 principles in the production, thus increasing the productivity and precision of the produced parts. It is very important to optimize all the production steps, from choosing the right CAD software for vectors drawing, defining tools and generating tool paths, creating and optimizing post-processor, to translating the tool paths in the programming code which controller of the CNC machine can understand, as well as educating the operators to be able to calibrate the machine and understand and run the CNC programming code properly. When all the abovementioned steps are correctly defined, the production can be optimized and best results are guaranteed.

A new cyber-physical adaptive control system for drilling of hybrid stacks

A new cyber-physical adaptive control system (CPACS) is presented for drilling hybrid stacks. A generalized approach for features recognition, and learning, of spindle power signals was developed for real-time detection of tool wear level. Subsequently, a high fidelity model predicts the drilling forces and the damage at the layers and interfaces of the stacked panel. The CPACS uses these predictions to maximize the feedrate while maintaining the damage-free force limit at each layer. The system communicates with the CNC machine controller to continuously update the drilling conditions. Validation test showed improved productivity and extended tool life while preserving part quality.

Development of a portable stereolithography device for computer numerical control machining centres

A low-cost portable stereolithography (SLA) device is designed to cure polymer resin at suitable laser light wavelength. Required motions are imparted by any three-axis CNC machining centre exploiting serial communication interface, macro programming and machine data manipulation facilities. The device consists of three subsystems: laser beam, resin handling and micro-controller, making use of several sensors and actuators. For an approximately circular beam spot the G-code is generated by commercially available slicing software and is automatically modified to comply with the CNC machine controller's own automation functions. Alternatively, for line-shaped laser beams G-code can be directly generated from STL files by making use of profiling and hatching library routines. The device has been tested with two different power diode lasers for manufacturing a variety of parts. Curing rate was tested by micro-hardness measurement. Dimensional accuracy with respect to nominal was recorded using a white-light scanner, proving that acceptable accuracy is reachable.

Development of a portable stereolithography device for computer numerical control machining centres

A low-cost portable stereolithography (SLA) device is designed to cure polymer resin at suitable laser light wavelength. Required motions are imparted by any three-axis CNC machining centre exploiting serial communication interface, macro programming and machine data manipulation facilities. The device consists of three subsystems: laser beam, resin handling and micro-controller, making use of several sensors and actuators. For an approximately circular beam spot the G-code is generated by commercially available slicing software and is automatically modified to comply with the CNC machine controller's own automation functions. Alternatively, for line-shaped laser beams G-code can be directly generated from STL files by making use of profiling and hatching library routines. The device has been tested with two different power diode lasers for manufacturing a variety of parts. Curing rate was tested by micro-hardness measurement. Dimensional accuracy with respect to nominal was recorded using a white-light scanner, proving that acceptable accuracy is reachable.

Using Fuzzy FMEA approach to improve decision-making process in CNC machine Electrical and control equipment failure prediction

Using Fuzzy FMEA approach to improve decision-making process in CNC machine Electrical and control equipment failure prediction

Elastyczny układ sterowania CNC maszyn bazujący na PC

In the article a PC-based CNC machine control system is presented which communicates with servo drives and auxiliary input/output devices via EtherCAT bus. LinuxRTAI real-time operating system and LinuxCNC control software were implemented in the PC controller. A software module implementing EtherCAT communication with the servo drives was developed and integrated with LinuxCNC. Experimental results were presented which show the trajectory smoothing capabilities of the control system. Experimental results were also presented that show following errors obtained by running an example trajectory on a linear motion module. Basic parameters that show the control systems capabilities obtained during the experimental tests have been presented. The CNC control system presented in this article was implemented on a 3-axis machine.

INTELLIGENT MACHINING: REAL-TIME TOOL CONDITION MONITORING AND INTELLIGENT ADAPTIVE CONTROL SYSTEMS

Unmanned manufacturing systems has recently gained great interest due to the ever increasing requirements of optimized machining for the realization of the fourth industrial revolution in manufacturing ‘Industry 4.0’. Real-time tool condition monitoring (TCM) and adaptive control (AC) machining system are essential technologies to achieve the required industrial competitive advantage, in terms of reducing cost, increasing productivity, improving quality, and preventing damage to the machined part. New AC systems aim at controlling the process parameters, based on estimating the effects of the sensed real-time machining load on the tool and part integrity. Such an aspect cannot be directly monitored during the machining operation in an industrial environment, which necessitates developing new intelligent model-based process controllers. The new generations of TCM systems target accurate detection of systematic tool wear growth, as well as the prediction of sudden tool failure before damage to the part takes place. This requires applying advanced signal processing techniques to multi-sensor feedback signals, in addition to using ultra-high speed controllers to facilitate robust online decision making within the very short time span (in the order of 10 ms) for high speed machining processes. The development of new generations of Intelligent AC and TCM systems involves developing robust and swift communication of such systems with the CNC machine controller. However, further research is needed to develop the industrial internet of things (IIOT) readiness of such systems, which provides a tremendous potential for increased process reliability, efficiency and sustainability.

An attempt of CNC machining cycle’s application as a tool of the design feature library elaboration

This paper presents a novel approach to a problem of the design feature library elaboration. As a tool of the design feature library development CNC machining cycles were proposed. Because of the great number of commercially available CNC machine controllers, with different CNC machining cycles definitions, it was necessary to make a decision about a research methodological framework, it is the selected CNC machine controller. Taking into account the criterion of popularity as the research framework the selected group of Sinumerik CNC machine controllers was chosen. Presented in the paper idea of the feature library development is based on an assumption saying that it is possible to find a relationship between a particular CNC machining cycle and the simple design feature or even compound design features. Identified, thanks to this assumption, set of the design features could be the base for elaboration of the design feature library. This solution, it is the feature library next gave opportunity for elaboration of the feature based design modelling module (FBDMM) working in the SIEMENS NX system environment. Hence, the FBDMM module can support both a designer and CNC machine programmer which is possible due to received in the module modelling paradigm. In FBDMM module the removal feature based modelling technique is received.

Development of a fiber optical occlusion based non-contact automatic tool setter for a micro-milling machine

The objective of this research is to create a low cost non-contact automated tool setter to reduce the overall tool setup time for a micro-milling machine. The accuracy of tool setting has a direct impact on the outcome of machining. The research focused on addressing the tool setting in the Z-axis (spindle axis), which is needed for each tool change and accounts for the majority of the total tool setting time. A fiber optic FS-V30M sensor from Keyence that is equipped with a light emitting element and receiving sensor was used. The sensor detects the position of the micro-tool by measuring the light intensity change as the tool crosses the emitted light beam. A bracket was designed and manufactured to mount on the workpiece pallet to hold the fiber optic cable. A novel search/detection algorithm was developed and implemented in the CNC machine controller. Controlled experiments were conducted to test the performance of the tool setter. The system achieved 0.6 µm repeatability and 2 µm accuracy across different sizes of micro-tools. The execution of each tool setting takes about 10 seconds, which is 80–90% reduction from the manual tool setting.

Serial control of CNC machines

In this paper a new method of the serial control of CNC machines is proposed. Actuators are controlled locally and the role of the central computer is limited to sending commands to the controller instead of sending it directly to actuators. It has been achieved with the use of the serial protocol with the use of the USB port. The taken approach leads to more reliable operation because commands are buffered and no synchronization between command stream and actuators operation is needed.

Surface Roughness Control Simulation of Turning Processes

The aim of this paper is to present a surface roughness control in turning with an associated simulation block diagram. The objective of the new model based controller is to assure the desired surface roughness by adjusting the machining parameters and maintaining a constant cutting force. It modifies the feed rate on-line to keep the surface roughness constant and to make machining more efficient. The control model was developed based on simplified models of the turning process and the feed drive servo-system. The experiments were performed to find the correlation between surface roughness and cutting forces in turning and to provide functional correlation with the controllable factors. Simulation setup and results are presented to demonstrate the efficiency of the proposed control model. In terms of surface roughness fluctuations and cutting efficiency, the suggested control model is much better than a conventional CNC controller alone. Integrating the developed control model with the CNC machine controller significantly improves the quality of machined components.

Data Structures Implementation of the Protocol Step-NC at CNC Machines Programming

Standard STEP-NC (ISO 14649) presents a new model for data transmission between CAD/CAM systems and CNC machines. This standard eliminates the shortcomings of the standard G-code and provides new possibilities in their management. At the Department of Automation and Production Systems, Faculty of Mechanical Engineering, University of Zilina in the framework of the research activities was solved a project for the implementation options of STEP-NC format by programming of CNC machines. This paper presents the results of research solutions which focused mainly on the analysis of standard STEP-NC, a methodology on the model data according to the standard STEP-NC using the EXPRESS language as well as the creation of software for the transformation of STEP-NC data - "TERMINAL STEP NC". The software has been verified in the transmission of STEP-NC data to a particular CNC machine control system. Transfer of STEP-NC data applications gives the possibility of verifying the implementation of the new standard in older types of CNC machines.

Interoperable CNC Machine via Function Block and STEP-NC Data Model for Milling Operation

The Function Block Development Kit (FBDK) platform proposed for STEP-NC controller architecture . It can be used to create an open CNC architecture on ISO 14649 and Function Block (IEC 61499). This offers interoperability, portability, and adaptability. The proposed framework consists of three main modules: (1) STEP-NC Interface, (2) Simulator, and (3) Communication. The system will be implemented in CNC controller on actual milling machine. It will simplify the design of CNC machine controller with the architecture layers responsible for data processing, data storage, execution and feedback. This paper also discusses towards the requirements for global interoperable manufacturing for real-life machining system with the architecture layers responsible for data storage, data processing, and execution.